Antismog carburetor

ABSTRACT

A vacuum-controlled valve is adapted to cut off the admission of fuel to a carburetor idling jet when the motor vehicle is decelerated and vacuum in the intake manifold is high. The engine thus acts as a brake, and when deceleration takes place to a predetermined extent, the drop in vacuum, that is, increase in pressure in the intake manifold, opens the valve to admit fuel to the carburetor to prevent the motor from stalling.

United States Patent [72] Inventor Alpha Severn 5316 S St., Sacramento,Calif. 95819 [211 App]. No 794,604 [22] Filed Jan. 28,1969 [45] PatentedNov. 9,1971

[54] ANTISMOG CARBURETOR l Clllm,3Drawlng Figs.

[52] U.S.Cl..l 261/41D, 261/69 R, 26l/DIG. 19,123/97 B [51] lnt.C1......F02m 7/12 [50] Field of Search 261/69, 39, 41,49,51,50.1,41.4; 123/97[56] References Cited UNITED STATES PATENTS 805,979 11/1905 Menges26l/D1G. 53 1,499,173 6/1924 Hansen-Ellehammer.... 261/69 1,933,39510/1934 Skoogh. .1 261/49 X 2,094,555 9/1937 Vonl-lilvety 123/97 PrimaryExaminer-Tim R. Miles Allorney- Alexander B. Blair ABSTRACT: Avacuum-controlled valve is adapted to cut off the admission of fuel to acarburetor idling jet when the motor vehicle is decelerated and vacuumin the intake manifold is high. The engine thus acts as a brake, andwhen deceleration takes place to a predetermined extent, the drop invacuum, that is, increase 111 pressure in the intake manifold, opens thevalve to admit fuel to the carburetor to prevent the motor fromstalling.

PATENTEDNUV SIS?! 3,618,907

INVENTOR.

41 MA SEVM/V I the relatively high degree of vacuum in 1 ANTISMOGcxnsuns'ron BACKGROUND OF THE INVENTION It is well known that carbonmonoxide and other noxious gases are discharged from a motor vehicleengine at a relatively high rate when the foot is removed from theaccelerator pedal and the vehicle is decelerated. This, of course, isdue to the intake manifold which causes excessive flow of fuel to thevehicle through the idling nozzle of the carburetor, it being impossiblefor complete combustion to take place in the absence of sufficient air.This causes a high rate of discharge of carbon monoxide and othernoxious gases and tends to cause smogging and substantially pollutes theatmosphere.

SUMMARY OF THE INVENTION Fuel is admitted from the float chamber of thecarburetor both to a carburetor running jet and to an idling jet justbeneath the throttle valve. A vertically movable valve stem has a valveat the bottom thereof and is movable downwardly to close communicationbetween the float chamber and the idling nozzle. The valve stem projectsupwardly through the float chamber and is provided with a roller at thetop thereof engageable by a cam to be nonnally held open. This cam isconnected to the diaphragm of a vacuum motor having a chambercommunicating with the intake manifold to be influenced by the degree ofvacuum therein. During deceleration of the vehicle with the acceleratorpedal released, vacuum in the intake manifold increases to a substantialextend, for example, to 22% inches of mercury. Under such conditions,the diaphragm of the vacuum motor moves the cam to drop the valve toclosed position. This completely cuts off the admission of fuel to thecarburetor through the idling jet and the vehicle engine accordinglyacts as a brake. When the vehicle has decelerated to a predetenninedextent, there will be a drop in vacuum in the intake manifold, that is,an increase in pressure, in which case the diaphragm returns to normalposition and opens the valve referred to to admit fuel through theidling jet, thus preventing motor stalling and providing sufficient fuelfor idling.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a sectional view through acarburetor, substantially simplified for the purpose of illustration,parts being shown .in elevation;

FIG. 2 is a section on line 2-2 of FIG. 1, and

FIG. 3 is a section on line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the numeraldesignates a downdraft carburetor as a whole having a mixing passage 12in the upper end of which is mounted the usual choke valve 14. Passageof.

crank arm 18 to a clockwise direction to open the throttle valve 14'.

The carburetor is enlarged at tone side as at 22 to provide a floatchamber 24 having a float 26 therein conventionally connected to aninlet valve (not shown) to control the admission of liquid fuel into thefloat chamber through an intake pipe 30.

The float chamber is provided with an outlet 32 leading in turn to arunning jet 34 opening into the mixing passage 12, the passage 32 alsobeing connected to a passage 36 leading to an idling jet 38 opening intothe passage 12 just below the adjacent edge of the choke valve 14. Theupper end of the passage 36 is provided with a valve seat 40.

A vertically slidable valve 42 is movable downwardly as described belowto close the valve seat 40 and thus close the passage 36. Two of thevalves 42 and associated elements are employed with a two-barrelcarburetor, and the valve 42 in FIG. 1 may be considered to be one ofsuch valves. The two valves for such a carburetor are shown in FIG. 3.

Assuming that the device is used on a two-barrel carburetor, each valve'62 will be provided with an upwardly extending stem 44 tied together asat 46. The stems 44 project upwardly through the cover plate 48 of thefloat chamber and then inwardly at their upward extremities as at 50 toengage in an axial opening in a roller 52 for which they form supportingshafts.

The roller 52 engages the top of a cam, indicated as a whole by thenumeral 54, having a horizontal high portion 56, and the cam slopesdownwardly towards it right-hand extremity in FIG. 1 as at 58. The righthand extremity of the cam is flattened as at 60 and slides over a rib 62formed on the cover 48 of the float chamber.

The cam 54 is provided with a straight shank 64, as shown in FIGS. l and2, and is connected at its extremity to a flexible diaphragm 68 of avacuum motor 70. The vacuum motor 70 comprises a pair of easing members72 and 74 in the latter of which is arranged a spring 76 biasing thediaphragm 68 to the right in FIG. 2 and is limited by a stop 78 tonormally position the cam surface 56 as shown in FIG. ii. The casing 74communicates through a nipple 80 with a flexible hose 82, the other endof which is connected to the intake manifold.

OPERATION As stated, the cam surface 56 is normally positioned as shownin FIG. ll, holding the valves 42 in their upper or open position.Liquid fuel accordingly may flow to both jet nozzles 34 and 38, thelatter of which primarily functions when the throttle valve 14' is inidling position. When the vehicle is being driven, the vacuum in theintake manifold will be relatively low and difi'erential pressure actingon opposite sides of the diaphragm 68 will not be sufficient to overcomethe loading of the spring '76.

When the vehicle is to be decelerated, the operator will remove his footfrom the accelerator pedal in which case the throttle valve 14' moves tothe idling position, shown in FIG. I. Therefore, the relatively highvacuum in the intake manifold, communicating with the lower end of themixing passage 12, causes too rapid a flow of fuel through the nozzle38, atmospheric pressure being present above the level of the fuel inthe float chamber 24. The relatively high vacuum in the intake manifoldcommunicated to the casing 74 of the vacuum motor 70, will now cause thediaphragm 68 to be subjected to atmospheric pressure at its right sidein FIG. 2 and the diaphragm will move against the spring 76 to move thecam 54 to the left in FIG. 1. The sloping portion 58 of the cam will nowmove beneath the roller 52, permitting this roller to drop together withthe stems 44 and valves 42. No liquid fuel accordingly will be admittedto the passage 36 and accordingly the engine will be used as a brakewithout the admission of fuel to the intake manifold and enginecylinders. It is under such conditions that excess fuel is fed to theengine and lack of air prevents complete combustion of the fuel with thepipe. With the present device, no fuel is supplied to the engine, hencethere will be no noxious fumes discharged through the exhaust pipe.

When vehicle deceleration has taken place to a predetermined point sothat there is a drop of vacuum in the intake manifold below, ferentialpressures affecting the diaphragm 68 will no longer be sufficient tocompress the spring 76, and the latter will move the diaphragm 68 andcam 54 back to its normal position, shown in FIG. 1, whereupon theidling jet 38, or jets in the case of a multibarrel carburetor, will beopened to admit fuel to the passage 12. This prevents the stalling ofthe engine for example 21 inches of mercury, the difregular carburetors,

there is a substantial rate of flow of fuel into the mixing passage,which not only results in exhausting noxious fumes, as stated, butperforms no useful function. With the present carburetor, the idling jetis completely cut off during vehicle deceleration, thus resulting in anappreciable saving of fuel.

From the foregoing it will now be seen that there is herein provided animproved antismog carburetor which accomplishes all of the objects ofthis invention and others, including many advantages of great practicalutility and commercial importance.

As various embodiments may be made of this inventive concept, and asmany modifications may be made in the embodiment hereinbeforc shown anddescribed, it is to be understood that all matter herein is to beinterpreted merely as illustrative, and not in a limiting sense.

I claim:

1. A carburetor having a mixing passage and a float chamber, an idling.jet, a duct connecting said float chamber to said idling jet, means forcompletely disconnecting said idling 5 jet from said float chamber whenintake manifold pressure is

